The architecture described in the material involves structuring the software into different levels (L1, L2, L3) and ensuring proper communication between hardware and software components. Below is a detailed breakdown of how to design the software:

1. Software Architecture Overview

The software architecture is divided into three levels:

Level 1 (L1): Hardware-specific programs that directly interact with sensors and actuators.

Level 2 (L2): Logic-defining programs that process data from L1 and send commands to actuators.

Level 3 (L3): High-level mission control programs that coordinate the overall behavior of the robot.

2. Level 1 (L1) Programs

These programs are responsible for direct communication with the hardware. For the Raspberry Pi 4, We will used libraries like gpiozero for GPIO control and pysicktim for LIDAR communication.

L1 Programs:

• L1_motor.py: Controls the motor drivers by generating PWM signals.

• L1_encoder.py: Reads data from wheel encoders.

• L1_lidar.py: Communicates with the LIDAR sensor to get distance measurements.

• L1_gamepad.py: Reads input from the gamepad controller.

• L1_camera.py: Captures images from the USB camera.

• L1_mpu.py: Reads data from the IMU (MPU9250) for orientation and motion data.

• L1_bmp.py: Reads temperature and pressure data from the BMP280 sensor.

• L1_adc.py: Reads voltage data from the ADC sensor.

3. Level 2 (L2) Programs

These programs process data from L1 and generate commands for actuators. They handle the logic for tasks like kinematics, speed control, and obstacle detection.

L2 Programs:

• L2_kinematics.py: Computes chassis movement based on wheel encoder data.

• L2_speed_control.py: Generates wheel duty cycle commands based on desired speed.

• L2_inverse_kinematics.py: Computes wheel vectors for desired movement.

• L2_obstacle.py: Processes LIDAR data to detect obstacles.

• L2_track_target.py: Processes camera data to track a target.

• L2_onboard.py: Computes battery and environmental data from BMP280 and ADC sensors.

• L2_log.py: Handles data logging for debugging and analysis.

4. Level 3 (L3) Programs

These programs coordinate the overall mission of the robot. They receive data from L2 programs and send high-level commands.

L3 Programs:

L3_drive_mt.py: Multithreaded driving program that coordinates movement based on gamepad input or autonomous commands.

L3_follow.py: Autonomous program for following a target using camera data.

L3_avoid_obstacles.py: Autonomous program for obstacle avoidance using LIDAR data.

5. Multithreading

To ensure smooth operation, especially for tasks like driving, obstacle detection, and audio feedback, multithreading is essential. Each thread should handle a specific task, such as:

Thread 1: Driving the robot based on gamepad input or autonomous commands.

Thread 2: Obstacle detection using LIDAR data.

Thread 3: Audio feedback or text-to-speech output.

6. Libraries and Dependencies

For the Raspberry Pi 4, you will use the following libraries:

gpiozero: For GPIO control.

pysicktim: For LIDAR communication.

numpy: For mathematical operations.

pygame: For gamepad input.

fastlogging: For logging data.

smbus2: For I2C communication with sensors like BMP280 and MPU9250.

Folder Structure

scuttle_robot/ ├── L1/ # Level 1: Hardware-specific programs │ ├── L1_motor.py │ ├── L1_encoder.py │ ├── L1_lidar.py │ ├── L1_gamepad.py │ ├── L1_camera.py │ ├── L1_mpu.py │ ├── L1_bmp.py │ └── L1_adc.py ├── L2/ # Level 2: Logic-defining programs │ ├── L2_kinematics.py │ ├── L2_speed_control.py │ ├── L2_inverse_kinematics.py │ ├── L2_obstacle.py │ ├── L2_track_target.py │ ├── L2_onboard.py │ └── L2_log.py ├── L3/ # Level 3: Mission control programs │ ├── L3_drive_mt.py │ ├── L3_follow.py │ ├── L3_avoid_obstacles.py │ └── L3_mission_control.py ├── utils/ # Utility functions and shared resources │ ├── constants.py │ └── logger.py └── main.py # Entry point for the system